Apparatus and method of adjusting automatic focus

ABSTRACT

An apparatus and method of adjusting an auto focus are provided. The apparatus includes: an imaging pickup device for generating an image signal by capturing light passing through an imaging lens; a shutter for controlling light exposure of the image pickup device; a focus detector that calculates a contrast value from the image signal and detecting a focus from the contrast value; and a release controller for controlling a release operation constituting a photographing operation of a still image, wherein the release controller includes, as driving modes, a first mode that directs a focus lens included in the imaging lens to be driven while driving the shutter, and a second mode that directs the focus lens not to be driven while driving the shutter. Accordingly, a photographing time is reduced.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims the benefit of Korean Patent Application No.10-2011-0057600, filed on Jun. 14, 2011, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND

The present invention relates to an apparatus and method of adjusting anauto focus.

In order for a digital photographing apparatus, such as a camera or acamcorder, to capture a clear still image or a clear moving image, it isrequired to accurately adjust a focus on a subject. Examples of a methodof adjusting an auto focus that automatically performs a focusadjustment include a method of adjusting a contrast auto focus and amethod of adjusting a phase difference auto focus.

According to the method of adjusting a contrast auto focus,photographing is performed while changing a location of a focus lenswhile obtaining a contrast value with respect to an image signalgenerated by an imaging sensor, and the focus lens is driven to a focuslens location where the contrast value is a peak contrast value.

According to the method of adjusting a phase difference auto focus, anindividual sensing device aside from an imaging sensor is used, and afocus location is detected from a phase difference of light applied tothe individual sensing device.

SUMMARY

The present invention provides an apparatus and method of adjusting anauto focus, where a photographing time is reduced.

According to an embodiment of the present invention, there is providedan apparatus for adjusting an auto focus, the apparatus including: animaging pickup device that generates an image signal by capturing lightpassing through an imaging lens; a shutter that controls light exposureof the image pickup device; a focus detector that calculates a contrastvalue from the image signal and detects a focus from the contrast value;and a release controller that controls a release operation constitutinga photographing operation of a still image, wherein the releasecontroller includes, as driving modes, a first mode that directs a focuslens included in the imaging lens to be driven while driving theshutter, and a second mode that directs the focus lens not to be drivenwhile driving the shutter.

The release controller may control the shutter and the focus lens suchthat a predetermined time interval is included between a point of timewhen the shutter starts to be driven and a point of time when the focuslens starts to be driven, in the first mode.

The apparatus may further include an exchangeable lens and a body unit,wherein the imaging lens may be included in the exchangeable lens, andthe image pickup device, the shutter, the focus detector, and therelease controller may be included in the body unit.

The exchangeable lens may further include: a lens storage unit thatstores power consumption information; and a communicator that transmitsthe power consumption information to the body unit, wherein the releasecontroller may select one of the driving modes according to the powerconsumption information.

The exchangeable lens may further include: a focus lens driver thatdrives the focus lens; a storage unit that stores driving speedinformation of the focus lens driver; and a communicator that transmitsthe driving speed information to the body unit, wherein the releasecontroller may select one of the driving modes according to the drivingspeed information.

The exchangeable lens may further include: a focus lens driver thatdrives the focus lens; a storage unit that stores at least one piece ofinformation of focus driving sensitivity information, focus lens driverinformation, and backlash information of the focus lens; and acommunicator that transmits the at least one piece of information to thebody unit, wherein the release controller may select one of the drivingmodes according to the at least one information.

The body unit may further include a display unit that displays acaptured image, and may stop a display on the display unit when therelease controller operates in the first mode.

The release controller may select one of the driving modes when thefocus lens is stopped.

According to another embodiment of the present invention, there isprovided an apparatus for adjusting an auto focus, the apparatusincluding: an image pickup device that generates an image signal bycapturing light passing through an imaging lens; a shutter that controlslight exposure of the image pickup device; a focus detector thatcalculates a contrast value from the image signal and detecting a focusfrom the contrast value; and a release controller that controls arelease operation constituting a photographing operation of a stillimage, wherein the release controller directs a focus lens included inthe imaging lens to be driven in a section from a point of time whenlight exposure for capturing the still image ends to a point of timewhen the shutter is closed.

The release controller may direct the focus lens to be driven in adirection opposite to a direction of driving the focus lens during thesection, after the section is ended.

The driving of the focus lens in the section may be a part of operationsfor detecting the focus.

The release controller may direct the focus lens to perform remainingoperations for detecting the focus by driving the focus lens in thedirection opposite to the a direction of driving the focus lens duringthe section, after the section is ended.

The release controller may control the shutter and the focus lens suchthat a predetermined time interval is included between a point of timewhen the shutter starts to be driven and a point of time when the focuslens starts to be driven, when the focus lens is directed to be drivenin the section.

The apparatus may further include an exchangeable lens and a body unit,wherein the imaging lens may be included in the exchangeable lens, andthe image pickup device, the shutter, the focus detector, and therelease controller may be included in the body unit.

The exchangeable lens may further include: a lens storage unit thatstores power consumption information; and a communicator that transmitsthe power consumption information to the body unit, wherein the releasecontroller may determine whether the focus lens is driven in the sectionaccording to the power consumption information.

The exchangeable lens may further include: a focus lens driver thatdrives the focus lens; a storage unit that stores driving speedinformation of the focus lens driver; and a communicator that transmitsthe driving speed information to the body unit, wherein the releasecontroller may determine whether the focus lens is driven in the sectionaccording to the driving speed information.

The exchangeable lens may further include: a focus lens driver thatdrives the focus lens; a storage unit that stores at least one piece ofinformation of focus driving sensitivity information, focus lens driverinformation, and backlash information of the focus lens; and acommunicator that transmits the at least one information to the bodyunit, wherein the release controller may determine whether the focuslens is driven in the section according to the at least one piece ofinformation.

The body unit may further include a display unit that displays acaptured image, and stop a display on the display unit when the releasecontroller drives the focus lens in the section.

The body unit may further include a release director that directs arelease operation that drives the focus lens and an iris to beperformed, and the release controller may direct the focus lens to bedriven in the section when the release director directs continuousphotographing.

According to another embodiment of the present invention, there isprovided a method of adjusting an auto focus of a digital photographingapparatus for capturing a still image according to a shutter signal, themethod including: driving a focus lens to adjust a focus; and driving ashutter according to capturing operations of the still image, whereinthe focus lens is driven while driving the shutter.

The driving of the shutter may include: driving the shutter beforestarting light exposure for current photographing; and driving theshutter after the light exposure is ended.

The focus lens may be driven for the current photographing while drivingthe shutter before starting the light exposure.

The focus lens may be driven for following photographing while drivingthe shutter after the light exposure is ended.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIG. 1 is a pictorial schematic diagram of a digital photographingapparatus according to an embodiment of the present invention;

FIG. 2 is a block diagram of a camera controller of the digitalphotographing apparatus of FIG. 1;

FIGS. 3A through 3D are graphs for describing an auto focus (AF)operation in a contrast AF method;

FIG. 4 is a timing diagram showing a general AF method;

FIG. 5 is a timing diagram showing an AF method according to anembodiment of the present invention;

FIG. 6 is a timing diagram showing an AF method according to anotherembodiment of the present invention;

FIGS. 7 through 10 are flowcharts illustrating a method of controlling abody unit of a digital photographing apparatus, according to anembodiment of the present invention;

FIG. 11 is tables showing lens data according to an embodiment of thepresent invention;

FIG. 12 is tables showing lens data according to another embodiment ofthe present invention;

FIG. 13 is a map diagram showing a focus lens moving according to an AFoperation;

FIGS. 14 through 16 are flowcharts illustrating a method of controllinga lens of a digital photographing apparatus, according to an embodimentof the present invention;

FIG. 17 is a timing diagram for describing an AF method according toanother embodiment of the present invention;

FIG. 18 is a timing diagram for describing an AF method according toanother embodiment of the present invention;

FIG. 19 is a timing diagram for describing an AF method according toanother embodiment of the present invention;

FIGS. 20A and 20B are flowcharts illustrating a method of controlling abody unit of a digital photographing apparatus, according to anotherembodiment of the present invention; and

FIGS. 21A and 21B are flowcharts illustrating a method of controlling abody unit of a digital photographing apparatus, according to anotherembodiment of the present invention.

DETAILED DESCRIPTION

Hereinafter, the present invention will be described more fully withreference to the accompanying drawings, in which exemplary embodimentsof the invention are shown and described in more detail below. Theinvention may, however, be embodied in many different forms and shouldnot be construed as being limited to the embodiments set forth herein;rather, these embodiments are provided so that this disclosure will bethorough and complete, and will fully convey the concept of theinvention to those skilled in the art. In the drawings, like referencenumerals denote like elements. Also, in the description below, detaileddescriptions about related well-known functions or configurations thatmay diminish the clarity of the points of the present invention areomitted.

FIG. 1 is a diagram of a digital photographing apparatus 1 according toan embodiment of the present invention.

Referring to FIG. 1, the digital photographing apparatus 1 according tothe current embodiment includes an exchangeable lens (hereinafter,referred to as a lens) 100 and a body unit 200. The lens 100 has a focusdetecting function and the body unit 200 has a function that drives afocus lens 104 by controlling the lens 100.

The lens 100 includes an image forming optical system 101, a zoom lenslocation detecting sensor 103, a lens driving actuator 105, a focus lenslocation detecting sensor 106, an iris driving actuator 108, a lenscontroller 110, and a lens mount 109.

The image forming optical system 101 includes a zoom lens 102 foradjusting a zoom, the focus lens 104 for changing a focus location, andan iris 107. The zoom lens 102 and the focus lens 104 may each be a lensgroup in which a plurality of lenses are combined.

The zoom lens location detecting sensor 103 and the focus lens locationdetecting sensor 106 respectively detect locations of the zoom lens 102and the focus lens 104. A timing of detecting the location of the focuslens 104 may be set by the lens controller 110 or a camera controller209 to be described later. For example, the timing of detecting thelocation of the focus lens 104 may be a timing of performing auto focus(AF) detection using an image signal.

The lens driving actuator 105 and the iris driving actuator 108 arecontrolled by the lens controller 110, and respectively drive the zoomlens 102 and the focus lens 104, and the iris 107. Specifically, thelens driving actuator 105 drives the focus lens 104 in an optical axisdirection.

The lens controller 110 includes a first timer 111 for measuring time.Also, the lens controller 110 transmits information about the detectedlocation of the focus lens 104 to the body unit 200. Here, the lenscontroller 110 may transmit the information about the detected locationof the focus lens 104 to the body unit 200 when the location of thefocus lens 104 is changed or when the camera controller 209 requestsinformation about the location of the focus lens 104. Also, the firsttimer 111 may be reset by a reset signal from the body unit 200, andtimes of the lens 100 and the body unit 200 may be synchronizedaccording to the reset.

The lens mount 109 includes a lens communication pin, and is used as atransmission path for data, a control signal, or the like by beinglinked to a camera communication pin.

A structure of the body unit 200 will now be described in detail.

The body unit 200 includes an electronic view finder (EVF) 201, ashutter 203, an image pickup device 204, an image pickup devicecontroller 205, a display unit 206, a manipulation button 207, thecamera controller 209, and a camera mount 208.

The EVF 201 may include a liquid crystal display unit 202, and a usermay view an image being captured in real time via the EVF 201.

The shutter 203 determines a duration in which light is applied to theimage pickup device 204, i.e., an exposure time.

The image pickup device 204 generates an image signal by capturing imagelight passed through the image forming optical system 101 of the lens100. The image pickup device 204 may include a plurality ofphotoelectric transformation units arranged in a matrix form, and atleast one of vertical and horizontal transmission paths for reading thegenerated image signal by transferring electric charges from thephotoelectric transformation units. A charge coupled device (CCD)sensor, a complementary metal oxide semiconductor (CMOS) sensor, or thelike may be used as the image pickup device 204.

The image pickup device controller 205 generates a timing signal, andcontrols the image pickup device 204 to capture an image insynchronization with the timing signal. Also, the image pickup devicecontroller 205 sequentially reads horizontal image signals afteraccumulation of electric charges is completed in each of scanning lines.The read horizontal image signals are used for the AF detection in thecamera controller 209.

The display unit 206 displays various images and information. An organiclight emitting display (OLED) or a liquid crystal display (LCD) may beused as the display unit 206.

The user inputs various commands to the manipulation button 207 tomanipulate the digital photographing apparatus 1. The manipulationbutton 207 may include various buttons, such as a shutter releasebutton, a main switch, a mode dial, and a menu button.

The camera controller 209 calculates a contrast value by performing theAF detection on the image signal generated by the image pickup device204. Also, the camera controller 209 stores a contrast value at each ofAF detecting points of time according to the timing signal generated bythe image pickup device controller 205, and calculates the focuslocation by using the information about the focus lens 104 received fromthe lens 100 and the stored contrast value. The calculated focuslocation is transmitted to the lens 100. The camera controller 209 mayinclude a second timer 228 for measuring time, and the second timer 228may be simultaneously reset with the first timer 111 so that the lens100 and the body unit 200 measure the same time.

The camera mount 208 includes a camera communication pin. Also, powermay be supplied to the lens controller 110 through the camera mount 208.

Schematic operations of the lens 100 and the body unit 200 will now bedescribed.

When a subject is to be photographed, an operation of the digitalphotographing apparatus 1 starts by manipulating the main switchincluded in the manipulation button 207. The digital photographingapparatus 1 first displays a live view as follows.

Image light of the subject passes through the image forming opticalsystem 101 and is incident on the image pickup device 204. At this time,the shutter 203 is in an open state. The incident image light isconverted into an electric signal by the image pickup device 204, andthus an image signal is generated. The image pickup device 204 operatesaccording to a timing signal generated by the image pickup devicecontroller 205. The generated image signal is converted into datadisplayable by the camera controller 209, and is output to the EVF 201and the display unit 206. Such an operation is called a live viewdisplay, and a live view image displayed according to the live viewdisplay is a moving image that is continuously displayed.

After the live view display, the digital photographing apparatus 1starts an AF operation when the shutter release button, which is one ofthe manipulation button 207, is half-pressed. The AF operation isperformed by using the image signal generated by the image pickup device204. According to a contrast AF method, a focus location is calculatedfrom a contrast value, and the lens 100 is driven based on thecalculated focus location. The contrast value is calculated by thecamera controller 209. The camera controller 209 calculates informationfor controlling the focus lens 104 from the contrast value, andtransmits the calculated information to the lens controller 110 throughthe lens communication pin and the camera communication pin respectivelyincluded in the lens mount 109 and the camera mount 208.

The lens controller 110 performs the AF operation by driving the focuslens 104 in the optical axis direction by controlling the lens drivingactuator 105 based on the received information. The location of thefocus lens 104 is monitored by the focus lens location detecting sensor106 and fed back to the camera controller 209.

When the zoom lens 102 is manipulated by the user to perform a zoomoperation, the zoom lens location detecting sensor 103 detects thelocation of the zoom lens 102, and the lens controller 110 changes AFcontrol parameters of the focus lens 104 to perform the AF operationagain.

When a focus on the subject is adjusted through the above operations,the shutter release button is completely pressed and thus the digitalphotographing apparatus 1 performs light exposure. Here, the cameracontroller 209 first completely closes the shutter 203, and thentransmits light measurement information obtained thus far to the lenscontroller 110 as iris control information. The lens controller 110controls the iris driving actuator 108 based on the iris controlinformation, and adjusts the iris 107 to have a suitable iris value. Thecamera controller 209 controls the shutter 203 based on the lightmeasurement information, and captures an image of the subject by openingthe shutter 203 for a suitable exposure time.

An image signal process and a compression process are performed on thecaptured subject image, and the processed subject image is stored in amemory card 212. At the same time, a captured image is output to the EVF201 and the display unit 206, where the subject is displayed. Such acaptured image is referred to as a quick view image.

Thus, the series of photographing operations are completed as describedabove.

FIG. 2 is a diagram of the camera controller 209 of the digitalphotographing apparatus 1 of FIG. 1, according to an embodiment of thepresent invention.

Referring to FIG. 2, the camera controller 209 according to the currentembodiment may include a pre-processor 220, a signal processor 221, acompression/decompression unit 222, a display controller 223, a centralprocessing unit (CPU) 224, a memory controller 225, an audio controller226, a card controller 227, the second timer 228, a power controller229, and a main bus 230.

The camera controller 209 transmits various directions and data tocorresponding elements through the main bus 230.

The pre-processor 220 performs an auto white balance (AWB) operation, anauto exposure (AE) operation, and an AF operation by receiving an imagesignal generated by the image pickup device 204. In other words, acontrast value for adjusting a focus, an AE evaluation value foradjusting exposure, and an AWB evaluation value for adjusting whitebalance are calculated.

The signal processor 221 performs a series of image signal processes,such as gamma correction, on the image signal generated by the imagepickup device 204 to prepare a live view image or a captured imagedisplayable on the display unit 206.

The compression/decompression unit 222 performs compression andextension on the image signal on which the image signal processes havebeen performed. According to the compression, for example, an imagesignal is compressed in a compression format, such as a JPEG compressionformat or an H.264 compression format. An image file including imagedata generated via the compression is transmitted to and stored in thememory card 212.

The display controller 223 controls image output to a display screen,such as the liquid crystal display unit 202 of the EVF 201 or thedisplay unit 206.

The CPU 224 controls overall operations of each element. Also, accordingto the digital photographing apparatus 1 of FIG. 1, the CPU 224communicates with the lens 100.

The memory controller 225 controls a memory 210 for temporarily storingdata, such as the captured image or image related information, and theaudio controller 226 controls a microphone or speaker 211. Also, thecard controller 227 controls the memory card 212 that stores thecaptured image.

The second timer 228 measures time by being simultaneously reset withthe first timer 111.

The power controller 229 controls power supply to the digitalphotographing apparatus 1 and to the lens controller 110.

FIGS. 3A through 3D are graphs for describing an AF operation in acontrast AF method. In the contrast AF method, the AF operation isperformed by detecting a location of a focus lens, where a contrastvalue of a subject is maximum, as a focus location. In FIGS. 3A through3D, a horizontal axis denotes a location of a focus lens, and a verticalaxis denotes a contrast value.

In FIG. 3A, a peak of a contrast value is detected by driving a focuslens in one direction at a high speed from a state where a contrastvalue is low as a subject is out of focus.

In FIG. 3B, the lens driving direction is reversed, and the peak isdetected again by driving the focus lens at a low speed compared to thehigh speed of FIG. 3A. Accordingly, the AF operation may be performedprecisely.

In FIG. 3C, the focus lens is driven toward a focus location accordingto the detected peak. However, a device that drives a lens generally hasbacklash, and an error may be generated in a lens location according toa driven direction. Accordingly, the focus lens is driven to passthrough the focus location in FIG. 3C in order to allow for removal ofthe error.

In FIG. 3D, the lens driving direction is again reversed and thus thefocus lens is driven in the same direction as in FIG. 3B where the focuslocation is finally determined, and the focus lens is stopped at thefocus location.

Thus, the AF operation is performed as described above.

An operation of photographing a subject according to the AF operationwill now be described in detail.

FIG. 4 is a timing diagram showing a general AF method. In other words,FIG. 4 is a timing diagram showing a focus lens not being driven, i.e.the AF operation is not performed during a release operation.

In FIG. 4, a horizontal axis denotes time, and a vertical axis denotes alocation of a focus lens. S1 and S2 respectively denote a photographingoperation start signal and a release start signal received from a user.Auto Focus denotes a driven state of the focus lens, and the focus lensis driven in a gray portion. OLED denotes a state of the display unit206. When the OLED is in a high level, an image of a subject isdisplayed on the display unit 206, and when the OLED is in a low level,a black screen is displayed on the display unit 206. Shutter denotes adriven state of a shutter driving actuator (not shown) for opening orshutting the shutter 203, and the shutter 203 is driven in grayportions. Also, a low level denotes a break state (pause state) and ahigh level denotes an off state. Diaphragm denotes a driven state of theiris 107, and the iris 107 is driven in gray portions. Expose denotes atiming when the subject image is exposed on the image pickup device 204,which begins when the shutter 203 is actually opened. Data Read denotesa timing when an image signal of the image pickup device 204 is recordedin a storage medium, while the Data Read is in a low level.

Referring to FIG. 4, the AF operation starts according to manipulationof S1 by the user at a time t1. First, as described with reference toFIGS. 3A through 3D, an operation A for detecting a peak of a contrastvalue at a high speed is performed. Since a peak location needs to bepassed to detect the peak of the contrast value at a time t2, a drivendirection of a lens is reversed at a time t3 when the peak location ispassed by a predetermined distance. Then an operation B for preciselydetecting the peak location is performed. Similarly, the peak locationis detected at a time t4, and the driven direction of the lens isreversed at a time t5 when the peak location is passed by apredetermined distance. At the time t5, a focus location is determinedto be the peak location detected at the time t4. An operation C isperformed toward the focus location, and an operation D is performed byreversing the driven direction of the lens again to compensate forbacklash at the time t6.

When a level of S2 is low at a time t7 when the operation D is completed(when the user requests release), a release operation starts. First, theshutter 203 is driven at a time t8 from an opened state to a closedstate by a shutter actuator (not shown). A direct current (DC) motor maybe used to drive the shutter 203, and a high current flows when the DCmotor starts to drive the shutter 203. Accordingly, at a time t9 after apredetermined time has passed after starting the driving of the shutter203, for example, after 15 ms, the iris 107 starts to be driven. Theiris 107 is driven by transmitting a command from the body unit 200 tothe lens 100 through the communication pin of the lens mount 109. Theshutter 203 is driven for a predetermined time, for example, 40 ms, andthen enters into a break state (pause state). An iris value of the iris107 changes according to luminance of the subject. However, the iris 107is driven for a predetermined time, for example, within 70 ms.

After the driving of the shutter 203 and iris 107 is completed, a lightexposure operation starts at a time t10. The shutter 203 is closed aftera time set according to a set shutter speed, and thus the light exposureoperation is completed at a time t11.

When the light exposure operation is completed, data is read from theimage pickup device 204 at a time t12. When the data is completely readat a time t13 after a predetermined time, for example, after 110 ms, theshutter 203 starts to be driven at a time t14 to open the shutter 203for following photographing. Here, as described above, the iris 107 isdriven to be opened at a time t15 after a predetermined time has passed,due to a driving current of the shutter actuator.

Embodiments of the present invention will now be described.

FIG. 5 is a timing diagram showing an AF method according to anembodiment of the present invention. FIG. 5 is a timing diagram showingdriving of the focus lens 104, i.e., when the AF operation is performed.

Referring to FIG. 5, operations at times t1 through t5 are identical tothose of FIG. 4.

Since a focus location is determined at the time t5, driving amounts inoperations C and D may also be determined. Times required to perform theoperations C and D are calculated according to the driving amounts anddriving speeds, and if the operations C and D are operable up to a timet10 when light exposure starts, a release operation starts at the sametime as with the operations C and D constituting the AF operation fromthe time t5. Here, since operations at times t6 through t16 areidentical to those of FIG. 4, details thereof will be omitted herein.

As shown in FIG. 5, the focus lens 104 is driven during the releaseoperation in the current embodiment. When compared with FIG. 4, aninterval from the time t5 when the operation B ends to the time t10 whenthe light exposure starts is clearly reduced in FIG. 5.

FIG. 6 is a timing diagram showing an AF method according to anotherembodiment of the present invention. FIG. 6 is a timing diagram when thefocus lens 104 is driven, i.e., when the AF operation is performed,wherein a driving speed of the focus lens 104 is slow. In a camerasystem using an exchangeable lens, a driving speed of a focus lens maydiffer according to a type of the exchangeable lens.

Referring to FIG. 6, when a driving speed of the focus lens 104 is slow,a point of time when operations C and D are completed may be behind atime t10 when light exposure starts, when times required to perform theoperations C and D are calculated at a time t5. In this case, theoperation C is performed first, and the time required to perform theoperation D is calculated again at a time t6. Here, while calculatingthe time required to perform the operation D, a driving time of abacklash amount required to reverse a driven direction of the focus lens104 is included. If the operation D is completed before the time t10,the release operation starts while starting the operation D. In otherwords, the release operation closing the shutter 203 starts at the timet8.

As shown in FIG. 6, according to the current embodiment, the focus lens104 is driven while performing the release operation. Compared with FIG.4, an interval from the time t6 when the operation C ends to the timet10 when the light exposure starts is clearly reduced in FIG. 6.

However, in FIGS. 5 and 6, the time t10 when the light exposure startsmay be behind the time t7 when the AF operation ends.

Operations of the body unit 200 according to FIGS. 5 and 6 will now bedescribed in detail.

FIGS. 7 through 10 are flowcharts illustrating a method of controllingthe body unit 200 of the digital photographing apparatus 1, according toan embodiment of the present invention. FIGS. 11 and 12 are tablesshowing lens data according to embodiments of the present invention.FIG. 13 is a diagram showing the focus lens 104 moving according to theAF operation.

Referring to FIG. 7, the body unit 200 first requests the lens 100 totransmit lens data in operation S101, and receives the lens data bycommunicating with the lens 100 in operation S102. The lens data willnow be described in detail with reference to FIGS. 11 and 12.

Referring to FIG. 11, “Focus Speed” denotes data indicating a drivingspeed of an AF of the lens 100. For example, the driving speed may be in10 stages from a lowest speed FS1 to a highest speed FS10. The drivingspeed may be indicated in a number of steps drivable in 1 second. Here,one step denotes a minimum unit of location control while performing theAF of the lens 100. In FIG. 11, the lens 100 is drivable at 2000 pulsesper second (pps) at the lowest speed FS1 and at 6500 pps at the highestspeed FS10. When directing the lens 100 to drive the focus lens 104, thebody unit 200 may select an optimum driving speed based on “FocusSpeed”, and the lens 100 may drive the focus lens 104 at the selecteddriving speed.

“Focus Sensitivity” is a coefficient for converting a defocusconstituting a lens defocus amount to a number of driving steps, anddenotes sensitivity of a focus driving amount with respect to a lensdriving amount. “Focus Sensitivity” includes data corresponding to focallengths of the zoom lens 102. For example, at a focal length Z1, “FocusSensitivity” is 0.32 pulse/micron, which means that the zoom lens 102 isdriven by 0.32 pulse to drive defocus of 1 micron.

“Backlash” denotes a backlash amount generated when a driven directionof the focus lens 104 is reversed, and is shown in units of pulses.According to the current embodiment, for example, 30 pulses of backlashare generated.

“Actuator” denotes data indicating a type of driving actuator for AF.“Actuator” stores data about selecting one of a DC motor, a step motor,an ultrasonic wave motor, and a voice coil motor. A step motor is usedin the current embodiment.

“Lens Power” denotes data indicating whether power consumption of anactuator of the lens 100 is equal to or above a base value. For example,the base value may be 2 A. When “Lens Power” is 0, the power consumptionmay be below or equal to the base value, and when “Lens Power” is 1, thepower consumption may be above the base value.

“Open Iris” denotes data of an open F number (FNo) according to thefocal lengths. Since the open F number changes according to a zoomingoperation of the zoom lens 102, “Open Iris” may include the open Fnumber for each of the focal lengths.

“Focus Length” indicates focal length information at each focal length.According to the current embodiment, for example, the lens 100 may be 28mm at a wide-end and 105.1 mm at a telephoto-end, wherein a focal lengthrange is divided into 8.

The lens data described above is only an example, and may differaccording to a type of the lens 100.

FIG. 12 shows a portion of another lens data of which is different fromthat of the lens 100 of FIG. 11. Here, the driving speed is slower andthe focus sensitivity is higher compared to the lens 100 of FIG. 11.

Referring back to FIG. 7, after the body unit 200 obtains the lens data,the body unit 200 drives the image pickup device 204 in operation S103,and displays a live view image on the display unit 206 in operationS104.

Then, the lens 100 is directed to be driven to perform the AF operationof FIGS. 3A through 3D in operation S105. In operation S105, theoperation A performed at a high speed is performed. For example, in theoperation A, a driving amount of the lens 100 is set to be F number×300μduring an AF obtaining period. Accordingly, when the lens 100 is locatedat a wide-end and the F number is 2.8, the lens 100 is moved by2.8×300μ=840μ in 16.7 ms (60 f/s), which is one detecting period. Thismeans that the lens 100 is driven by about 50400μ in 1 second. When thedriving amount is converted into a driving speed, for example, when thedriving amount is multiplied by 0.16 of “Focus Sensitivity” of FIG. 11,the lens 100 is driven at a speed of 8064 pps. However, since the lens100 cannot be driven at 8064 pps in FIG. 11, the lens 100 is driven at amaximum speed of 6500 pps.

When the operation A starts to be performed, a contrast value of asubject for the AF is obtained at every one frame, that is, a period inwhich image information is updated, in operations S106 and S107. Then,it is determined whether a peak location of the contrast value isdetected in operation S108. For example, contrast values detected inframes may be compared, and it may be determined that the peak locationis detected if the contrast values decreases for 2 consecutive framescompared to the contrast value detected in a certain previous frame. Inother words, if C(n−1), C(n), C(n+1), and C(n+2) respectively denotecontrast values obtained in frames n−1, n, n+1, and n+2, C(n) may bedetermined to be a peak when C(n)>C(n−1), C(n)>C(n+1), andC(n+1)>C(n+2). When it is determined that the peak location is detected,the focus lens 104 stops being driven in operation S109.

Then, the operation B is performed in operation S110 to precisely detecta focus location. In the operation B, the driving amount of the lens 100is set to be F number×150μ during the AF obtaining period. Accordingly,when the lens 100 is located at a wide-end and the F number is 2.8, thelens 100 is moved by 2.8×150μ=420μ in 16.7 ms (60 f/s), which is onedetecting period. This means that the lens 100 is driven by about 25200μin 1 second. When the driving amount is converted into a driving speed,for example, when the driving amount is multiplied by 0.16 of “FocusSensitivity” of FIG. 11, the lens 100 is driven at a speed of 4032 pps.However, since there is no speed corresponding to 4032 pps in FIG. 11,the lens 100 is driven at a maximum speed of 4000 pps closet to 4032pps.

When the operation B starts to be performed, the contrast value of thesubject for the AF is obtained at every one frame, that is, the periodin which image information is updated, in operations S111 and S112.Then, it is determined whether the peak location of the contrast valueis detected in operation S113. When it is determined that the peaklocation is detected, the focus lens 104 stops being driven in operationS114.

Also, in order to more precisely detect the focus location, the focuslocation is accurately calculated in operation S115 by performinginterpolation calculation using the contrast values of C(n−1), C(n), andC(n+1) and the location of the focus lens 104 from the frames where thecontrast values are detected. Then, a message that the AF operation hassucceeded is displayed in operation S116.

The method will now be described with reference to FIGS. 8A and 8B.

Referring to FIGS. 8A and 8B, a driving amount of the operations C and Dthat drives the focus lens 104 to the calculated focus location duringthe AF operation are calculated in operation S201. The driving amount iscalculated based on a current location of the focus lens 104, the focuslocation, and a backlash amount. The driving amount may be obtained byadding a driving amount of the operation C, a driving amount of theoperation D, and a driving amount according to a double backlash amountdue to two driven direction reversals during the operations C and D. Thecalculating of the driving amount will now be described in detail withreference to FIG. 13.

FIG. 13 is a diagram showing the focus lens 104 moving according to theAF operation. In FIG. 13, a horizontal axis denotes the location of thefocus lens 104. The focus lens 104 may be driven from infinitephotographing distance to a close photographing distance.

Operation S201 is performed at a point of time when the operations A andB described above are completed, and the focus lens 104 is located at alocation PC. The operations C and D are performed from the location PC,and a driving amount from the location PC to a focus location Pinfocusis calculated. The driving amount of the operation C is determined byadding a difference between the location PC and the focus locationPinfocus and a number of steps required to perform a reverse operation.In other words, as shown in FIG. 13, the total driving amount of theoperations C and D is obtained by adding the driving amount of theoperation C, the driving amount of the operation D, and the drivingamount according to backlash indicated by a dotted line.

For example, when the driving amount of the operation C is 280 steps andthe driving amount of the operation D is 80 steps, the driving amount ofthe operations C and D is 360 steps. When the driving amount accordingto the backlash, here, 30 steps, is added twice, a driving amount of 420steps is obtained, and the 420 steps is the total driving amount of theoperations C and D.

Also, a driving time is calculated by applying a maximum speed of “FocusSpeed” to the total driving amount in operation S202. Since the maximumspeed is 6500 pps, the driving time according to the current embodimentis 65 ms. The driving time is only an example, and may vary according to“Focus Speed”, “Focus Sensitivity”, and “Backlash” of a lens.

Referring back to FIG. 8A, it is determined whether S2 requesting toperform a release operation is in a low level (L) in operation S203.

When S2 is in a high level (H), that is, there is no request to performthe release operation, the operations C and D are performed in operationS210. Then, it is determined whether the operations C and D are ended inoperation S211, and if the operations C and D are ended, it is againdetermined whether S2 is in the low level or the high level in operationS212. If S2 is determined to be in the low level, the release operationstarts to be performed, and if S2 is determined to be in the high level,operation S213 for determining whether S1 is in a low level isperformed.

When S1 is in the low level, operation S212 is performed, and when S1 isin a high level, the body unit 200 enters into a sleep mode.

Meanwhile, if S2 is determined to be in the low level in operation S203,i.e., when the release operation is requested, it is determined if “LensPower” data is 0 in operation S204. When the “Lens Power” data is 1 andthus the power consumption of the lens 100 exceeds 2 A, it is difficultto simultaneously drive the shutter 203, the iris 107, and the focuslens 104. Accordingly, operation S209 is performed to end the driving ofthe focus lens 104 before the release operation. Alternatively, when the“Lens Power” data is 0, it is determined whether the lens drivingactuator 105 is a DC motor in operation S205. If it is determined thatthe lens driving actuator 105 is a DC motor, operation S109 is performedto end the driving of the focus lens 104 before the release operationsince the DC motor has a high driving current. If the lens drivingactuator 105 is not a DC motor, it is determined whether the drivingtime calculated in operation S202 is within a predetermined value inoperation S206. Here, the predetermined value may be a value enablingthe time t7 of FIG. 7 when the operations C and D are ended to be thetime t10 when the light exposure starts. Alternatively, thepredetermined value may be a time required to process the releaseoperation, wherein the driving of the shutter 203 and the iris 107 areperformed during this time. For example, the predetermined value may be70 ms.

When a driving time of the operations C and D is determined to be within70 ms in operation S206, displaying of the live view image is stopped toreduce power consumption, and a black screen is displayed on the displayunit 206 in operation S207. Then, the operations C and D are directed tobe performed on the lens 100 in operation S208. Then, the body unit 200stands by for a predetermined time, for example, after about 10 ms,after directing the operations C and D to be performed, in operationS209.

When it is determined that the driving time is equal to or above 70 msin operation S206, the AF operation does not end during the releaseoperation. Accordingly, the operation C is performed and then ended inoperations S214 and S215. Then, a driving time of the operation D iscalculated again in operation S216. Here, the driving time is calculatedby adding the backlash amount to the driving amount of the operation D.For example, when the driving amount of the operation D is 80 steps andthe driving amount of the backlash is 30 steps, the total driving amountof the operation D is 110 steps. When the operation D is performed atthe driving speed of 6500 pps, the driving time is 17 ms.

After calculating the driving time of the operation D, it is determinedwhether the driving time is within a predetermined value in operationS217. When the driving time of the operation D is within thepredetermined value, for example, within 70 ms, the displaying of thelive view image is stopped, and a black screen is displayed on thedisplay unit 206 in operation S220. Then, the lens 110 is directed toperform the operation D in operation S221, and the release operation isperformed after standing by for a predetermined time in operation S222.

Alternatively, when the driving time is determined to be equal to orabove the predetermined value in operation S217, the operation D isperformed in operation S218, and the end of the operation D isdetermined in operation S219. Then, the release operation is performedafter the operation D is ended.

Next, the method will be described with reference to FIG. 9.

Referring to FIG. 9, when the release operation starts, a black screenis displayed on the display unit 206, and it is displayed to the userthat the release operation is being performed, in operation S301. Whenan OLED is used as the display unit 206, power consumption is almostproportional to display luminance since the OLED is a self-emissiondisplay device. Accordingly, by displaying a black screen, requiredpower is reduced, thereby increasing power supplied to an actuator orthe like during the release operation.

The image pickup device 204 is entered into a still image capture modein operation S302, and the shutter 203 is changed from an open state todisplay a live view image to a closed state in operation S303. Since aDC motor is used as an actuator that drives the shutter 203, a highdriving current is required to start driving the shutter 203.Accordingly, the body unit 200 stands by for a predetermined time, forexample, about 15 ms, in operation S304 after the shutter 203 starts tobe driven, and directs the lens 100 to drive the iris 107 in operationS305.

The body unit 200 stands by for a predetermined time, for example, about40 ms, to end the driving of the shutter 203 in operation S306, and thena shutter brake is put on the shutter 203 in operation S307. Then, thebody unit 200 stands by for a predetermined time, for example, about 15ms, to end the driving of the iris 107 in operation S308, and then it isdetermined whether the AF operation and the driving of the iris 107 areended respectively in operation S309 and S310.

When the AF operation or the driving of the iris 107 is not ended, it isdetermined that a mechanical error has been generated, and thus an errorprocess is performed. When the AF operation and the driving of the iris107 are normally ended, light exposure starts to be performed.

Next, the method will now be described with respect to FIG. 10.

Referring to FIG. 10, when the light exposure starts to be performed, afirst sheet or a front sheet of the shutter 203 is driven in operationS401. Accordingly, an exposure time is counted in operation S402. When apredetermined exposure time has passed, a second sheet or a rear sheetis driven in operation S403.

After the first and second sheets are driven, an image signal is read inoperation S404 by a CMOS image sensor constituting the image pickupdevice 204. When it is determined that operation S404 has been performedon all pixels in operation S405, an image signal process foraccumulating an image as an image file is performed in operation S406.

Then, since all pixels are read, the shutter 203 is opened in operationS407 for following photographing, and then the body unit 200 stands byfor a predetermined time, for example, about 15 ms, in operation S408.

The lens 100 is directed to start opening the iris 107 after the standbyin operation S409, and the body unit 200 stands by for a predeterminedtime, for example, about 40 ms, in operation S410.

After 40 ms, the driving of the shutter 203 is stopped and thus ashutter brake is put on the shutter 203 in operation S411, and the bodyunit 200 stands by for a predetermined time, for example, about 25 ms,in operation S412. Then, it is determined whether S1 is in the low levelin operation S413. If S1 is in the low level, the AF operation is againperformed, and if S1 is in the high level, the body unit 200 is enteredinto the sleep mode since the digital photographing apparatus 1 is notbeing manipulated.

As such, the AF operation and the release operation are performed by thebody unit 200.

Operations of the lens 100 will now be described in detail.

FIGS. 14 through 16 are flowcharts illustrating a method of controllingthe lens 100 of the digital photographing apparatus 1, according to anembodiment of the present invention.

Referring to FIG. 14, when the lens 100 starts to be driven, it isdetermined whether the AF operation is being performed in operationS501. When the AF operation is being performed, it is determined whetherthe AF operation is ended in operation S502. When the AF operation isended, an AF operation driving flag is released in operation S503, andan AF operation end signal is transmitted to the body unit 200 inoperation S504.

When the AF operation is not being performed or the AF operation isended, it is determined whether the iris 107 is being driven inoperation S505. If the iris 107 is being driven, it is determinedwhether the driving of the iris 107 is ended in operation S506. If thedriving of the iris 107 is ended, an iris driving flag is released inoperation S507, and an iris driving end signal is transmitted to thebody unit 200 in operation S508.

If the iris 107 is not being driven or the driving of the iris 107 isended, it is determined whether the body unit 200 requested to transmitlens data in operation S509. If the lens data is requested, the lensdata is set in operation S510, the set lens data is transmitted to thebody unit 200 in operation S511, and then operations S501 through S510are performed again.

Referring to FIG. 15, if the body unit 200 did not request to transmitthe lens data, it is determined whether the AF operation is requested tobe stopped in operation S601. If the AF operation is requested to bestopped, the driving of the focus lens 104 is immediately stopped inoperation S602, and a focus lens driving flag is released in operationS603. Then, an AF operation end signal is transmitted to the body unit200 in operation S604.

Meanwhile, if the AF operation is not requested to be stopped, it isdetermined whether the AF operation is requested to be performed inoperation S605. If the AF operation is requested to be performed, adriving speed and a driving amount of the AF operation are set inoperation S606 according to a direction of the body unit 200, and an AFoperation driving flag is set in operation S607. Then, the AF operationstarts to be driven in operation S608.

Alternatively, if the AF operation is not requested to be performed inoperation S605, it is determined whether the iris 107 is requested to bedriven in operation S609. If the iris 107 is requested to be driven, adriving speed and a driving amount of the iris 107 are set in operationS610 according to the direction of the body unit 200, and an irisdriving flag is set in operation S611. Then, the iris 107 is driven inoperation S612. If the iris 107 is not requested to be driven inoperation S609, the lens 100 starts to be driven to control a followingloop.

FIG. 16 shows a case when data is received from the body unit 200. Aninterrupt process is performed on the data from the body unit 200according to an update request from the body unit 200.

Upon receiving a command from the body unit 200 in operation S701, thedata is set according to the received command via the interrupt processin operation S702. After the data is set, the lens 100 returns from aninterrupt process loop (returns from an interrupt routine (RETI)), inoperation S703.

As such, the lens 100 performs the AF operation and the releaseoperation according to the current embodiment of the present invention.

According to the digital photographing apparatus 1, the AF operation isperformed while performing the release operation, thereby reducing aphotographing time, as described above.

FIGS. 17 through 19 are timing diagrams for describing an AF methodaccording to other embodiments of the present invention. Here, FIGS. 17through 19 show driving timings of the focus lens 104 performed while animage signal is read and the shutter 203 is opened after light exposure.

Referring to FIG. 17, the focus lens 104 is not driven while the imagesignal is read and the shutter 203 is opened. Operations at times t1through t16 in FIG. 17 are identical to those in FIG. 5, and thusdetails thereof will not be repeated.

When the digital photographing apparatus 1 is in a continuousphotographing mode, a following photographing operation is performedwhen the release operation is ended at the time t16. At this time, sincethe AF operation is performed during a previous release operation, thefocus lens 104 is located around the focus location. Accordingly, anoperation E is performed by first moving the location of the focus lens104 from its current location to detect a peak of a contrast value. Whenthe operation E ends at a time t2-3, the focus location is determined atthe time t2-3 during a second AF operation. Also, when the shutter 203is opened due to a second release operation at a time t2-8, the iris 107starts to be driven at a time t2-9. Accordingly, the AF operation isperformed during the release operation, like the first photographing.

FIG. 18 is a timing diagram of starting the AF operation while readingthe image signal. A time required to perform the operation E iscalculated based on a driving amount and a driving speed of theoperation E at the time t12 when the image signal starts to be readafter the light exposure, and then the operation E is performed if theoperation E can be ended by the time t13 when the reading of the imagesignal ends.

According to the current embodiment, a time from the time t16 whensecond photographing starts to a time when second light exposure startsin FIG. 18 may be reduced compared to that of FIG. 17.

FIG. 19 is a timing diagram of starting the AF operation while openingthe shutter 203 and driving the iris 107 after first photographing.After opening the shutter 203 for a second time at the time t14, theiris 107 is driven while being opened at the time t15 after 15 ms. Theoperation E of the AF operation is performed at the time t17 after 15 msafter the iris 107 starts to be driven. Also, an operation 2-Bconstituting a following AF operation is performed at the time t16 whenthe first photographing is ended.

According to the current embodiment, a time from the time t16 whensecond photographing starts to a time when second light exposure startsin FIG. 19 may be reduced compared to that of FIG. 17.

Meanwhile, in FIGS. 18 and 19, the operation E may be ended before thetime t16 when the first photographing ends.

Operations of the body unit 200 according to FIGS. 18 and 19 will now bedescribed in detail.

FIGS. 20A and 20B are flowcharts illustrating a method of controllingthe body unit 200 of the digital photographing apparatus 1, according toanother embodiment of the present invention. In FIGS. 20A and 20B, thebody unit 200 performs an operation for a following AF operation whilethe image pickup device 204 reads an image signal after light exposure,and thus FIGS. 20A and 20B shows processes after the light exposure. Inother words, operations of FIGS. 20A and 20B are operations replacingoperations after the light exposure of FIG. 10, with respect to theembodiments of FIGS. 7 through 10 and FIGS. 14 through 16. Descriptionsabout operations similar to those of FIG. 10 will not be repeatedherein.

Referring to FIGS. 20A and 20B, a first sheet starts to be driven inoperation S801, an exposure time is counted in operation S802, a secondsheet starts to be driven in operation S803, and then the image pickupdevice 204 starts reading an image signal in operation S804. Then, “LensPower” data is checked in operation S805, and if the “Lens Power” datais 0 and thus power consumption is low, it is determined whether anactuator is a DC motor in operation S806. If the actuator is not a DCmotor, the driving amount and the driving time of the operation E arecalculated respectively in operations S807 and S808. Since the method ofcalculating the driving amount and the driving time is described abovewith respect to the AF operation, details about the method will not berepeated herein.

Next, it is determined whether the calculated driving time is within atime taken to read the image signal, for example, within 110 ms, inoperation S809. If the driving time is within 110 ms, the lens 100 isdirected to perform the operation E in operation S810.

Meanwhile, if the driving time is not within 110 ms, the AF operation isnot performed while reading the image signal from all pixels.Alternatively, when “Lens Power” data is 1 or when the actuator is a DCmotor, the operation E is not performed.

When all pixels are read in operation S811, an image signal process isperformed in operation S812. Then, the shutter 203 is opened and theiris 107 is driven, and S1 is determined for a following AF operation inoperations S813 through S819.

FIGS. 21A and 21B are flowcharts illustrating a method of controllingthe body unit 200 of the digital photographing apparatus 1, according toanother embodiment of the present invention. In FIGS. 21A and 21B, thebody unit 200 performs an operation for a following AF operation whileopening the shutter 203, and thus FIGS. 21A and 21B shows processesafter the light exposure. In other words, operations of FIGS. 21A and21B are operations replacing operations after the light exposure of FIG.10, with respect to the embodiments of FIGS. 7 through 10 and FIGS. 14through 16. Descriptions about operations similar to those of FIG. 10will not be repeated herein.

Referring to FIGS. 21A and 21B, a first sheet starts to be driven inoperation S901, an exposure time is counted in operation S902, a secondsheet starts to be driven in operation S903, and then the image pickupdevice 204 starts reading an image signal in operation S904. When allpixels are read in operation S905, an image signal process is performed,the shutter 203 is opened, the iris 107 is driven, etc., in operationsS906 through S909. The body unit 200 stands by for a predetermined time,for example, about 15 ms, in operation S910, after the iris 107 isdriven.

Then, “Lens Power” data is checked in operation S911, and if the “LensPower” data is 0 and thus power consumption is low, it is determinedwhether an actuator is a DC motor in operation S912. If the actuator isnot a DC motor, the driving amount and the driving time of the operationE are calculated respectively in operations S913 and S914. Since themethod of calculating the driving amount and the driving time isdescribed above with respect to the AF operation, details about themethod will not be repeated herein.

Then, it is determined whether the driving time is within apredetermined time, for example, within 50 ms, in operation S915. Here,the predetermined time denotes a time when a point of time when theoperation E ends according to the driving time is the time t16 whenfirst photographing ends. If the driving time is within 50 ms, the lens100 is directed to start performing the operation E in operation S916.

Alternatively, when the driving time is not within 50 ms, the operationE is not performed while opening the shutter 203. Alternatively, whenthe “Lens Power” data is 1 or the actuator is a DC motor, the operationE is not performed.

Lastly, the opening of the shutter 203 and the driving of the iris 107are performed and then ended, and a level of S1 is determined for afollowing AF operation in operations S917 through S920.

As described above, according to the digital photographing apparatus 1,the photographing time may be reduced by performing the AF operation forthe following photographing while performing the release operation.

While describing the embodiments of the present invention, the values ofthe driving time and the driving amount are only examples, and may vary.

The system or systems described herein may be implemented on any form ofcomputer or computers and the components may be implemented as dedicatedapplications or in client-server architectures, including a web-basedarchitecture, and can include functional programs, codes, and codesegments. Any of the computers may comprise a processor, a memory thatstores program data and executing it, a permanent storage such as a diskdrive, a communications port for handling communications with externaldevices, and user interface devices, including a display, keyboard,mouse, etc. When software modules are involved, these software modulesmay be stored as program instructions or computer readable codesexecutable on the processor on a computer-readable media such asread-only memory (ROM), random-access memory (RAM), CD-ROMs, magnetictapes, floppy disks, and optical data storage devices. The computerreadable recording medium can also be distributed over network coupledcomputer systems so that the computer readable code is stored andexecuted in a distributed fashion. This media is readable by thecomputer, stored in the memory, and executed by the processor.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedas incorporated by reference and were set forth in its entirety herein.

For the purposes of promoting an understanding of the principles of theinvention, reference has been made to the preferred embodimentsillustrated in the drawings, and specific language has been used todescribe these embodiments. However, no limitation of the scope of theinvention is intended by this specific language, and the inventionshould be construed to encompass all embodiments that would normallyoccur to one of ordinary skill in the art.

The present invention may be described in terms of functional blockcomponents and various processing steps. Such functional blocks may berealized by any number of hardware and/or software components thatperform the specified functions. For example, the present invention mayemploy various integrated circuit components, e.g., memory elements,processing elements, logic elements, look-up tables, and the like, whichmay carry out a variety of functions under the control of one or moremicroprocessors or other control devices. Similarly, where the elementsof the present invention are implemented using software programming orsoftware elements the invention may be implemented with any programmingor scripting language such as C, C++, Java, assembler, or the like, withthe various algorithms being implemented with any combination of datastructures, objects, processes, routines or other programming elements.Functional aspects may be implemented in algorithms that execute on oneor more processors. Furthermore, the present invention could employ anynumber of conventional techniques for electronics configuration, signalprocessing and/or control, data processing and the like. The words“mechanism” and “element” are used broadly and are not limited tomechanical or physical embodiments, but can include software routines inconjunction with processors, etc.

The particular implementations shown and described herein areillustrative examples of the invention and are not intended to otherwiselimit the scope of the invention in any way. For the sake of brevity,conventional electronics, control systems, software development andother functional aspects of the systems (and components of theindividual operating components of the systems) may not be described indetail. Furthermore, the connecting lines, or connectors shown in thevarious figures presented are intended to represent exemplary functionalrelationships and/or physical or logical couplings between the variouselements. It should be noted that many alternative or additionalfunctional relationships, physical connections or logical connectionsmay be present in a practical device. Moreover, no item or component isessential to the practice of the invention unless the element isspecifically described as “essential” or “critical”.

The use of “including,” “comprising,” or “having” and variations thereofherein is meant to encompass the items listed thereafter and equivalentsthereof as well as additional items. Unless specified or limitedotherwise, the terms “mounted,” “connected,” “supported,” and “coupled”and variations thereof are used broadly and encompass both direct andindirect mountings, connections, supports, and couplings. Further,“connected” and “coupled” are not restricted to physical or mechanicalconnections or couplings.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) should be construed to cover both the singular and theplural. Furthermore, recitation of ranges of values herein are merelyintended to serve as a shorthand method of referring individually toeach separate value falling within the range, unless otherwise indicatedherein, and each separate value is incorporated into the specificationas if it were individually recited herein. Finally, the steps of allmethods described herein are performable in any suitable order unlessotherwise indicated herein or otherwise clearly contradicted by context.The use of any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. Numerous modifications and adaptations will bereadily apparent to those skilled in this art without departing from thespirit and scope of the present invention.

What is claimed is:
 1. An apparatus for adjusting an auto focus, theapparatus comprising: an imaging pickup device that generates an imagesignal by capturing light passing through an imaging lens; a shutterthat controls light exposure of the image pickup device; a focusdetector that calculates a contrast value from the image signal anddetects a focus from the contrast value; and a release controller thatcontrols a release operation constituting a photographing operation of astill image, wherein the release controller comprises, as driving modes,a first mode that directs a focus lens included in the imaging lens tobe driven while driving the shutter, and a second mode that directs thefocus lens not to be driven while driving the shutter.
 2. The apparatusof claim 1, wherein the release controller controls the shutter and thefocus lens such that a predetermined time interval is included between apoint of time when the shutter starts to be driven and a point of timewhen the focus lens starts to be driven, in the first mode.
 3. Theapparatus of claim 1, further comprising: an exchangeable lens and abody unit, wherein the imaging lens is included in the exchangeablelens, and the image pickup device, the shutter, the focus detector, andthe release controller are included in the body unit.
 4. The apparatusof claim 3, wherein the exchangeable lens further comprises: a lensstorage unit that stores power consumption information; and acommunicator that transmits the power consumption information to thebody unit, wherein the release controller selects one of the drivingmodes according to the power consumption information.
 5. The apparatusof claim 3, wherein the exchangeable lens further comprises: a focuslens driver that drives the focus lens; a storage unit that storesdriving speed information of the focus lens driver; and a communicatorthat transmits the driving speed information to the body unit, whereinthe release controller selects one of the driving modes according to thedriving speed information.
 6. The apparatus of claim 3, wherein theexchangeable lens further comprises: a focus lens driver that drives thefocus lens; a storage unit that stores at least one piece of informationof focus driving sensitivity information, focus lens driver information,and backlash information of the focus lens; and a communicator thattransmits the at least one piece of information to the body unit,wherein the release controller selects one of the driving modesaccording to the at least one information.
 7. The apparatus of claim 3,wherein the body unit further comprises a display unit for displaying acaptured image, and stops a display on the display unit when the releasecontroller operates in the first mode.
 8. The apparatus of claim 1,wherein the release controller selects one of the driving modes when thefocus lens is stopped.
 9. An apparatus for adjusting an auto focus, theapparatus comprising: an image pickup device that generates an imagesignal by capturing light passing through an imaging lens; a shutterthat controls light exposure of the image pickup device; a focusdetector that calculates a contrast value from the image signal anddetecting a focus from the contrast value; and a release controller thatcontrols a release operation constituting a photographing operation of astill image, wherein the release controller directs a focus lensincluded in the imaging lens to be driven in a section from a point oftime when light exposure for capturing the still image ends to a pointof time when a reading of image data ends.
 10. The apparatus of claim 9,wherein the release controller directs the focus lens to be driven in adirection opposite to a direction of driving the focus lens during thesection, after the section is ended.
 11. The apparatus of claim 9,wherein the driving of the focus lens in the section is a part ofoperations for detecting the focus.
 12. The apparatus of claim 11,wherein the release controller directs the focus lens to performremaining operations for detecting the focus by driving the focus lensin the direction opposite to the a direction of driving the focus lensduring the section, after the section is ended.
 13. The apparatus ofclaim 9, wherein the release controller controls the shutter and thefocus lens such that a predetermined time interval is included between apoint of time when the shutter starts to be driven and a point of timewhen the focus lens starts to be driven, when the focus lens is directedto be driven in the section.
 14. The apparatus of claim 9, furthercomprising: an exchangeable lens and a body unit, wherein the imaginglens is included in the exchangeable lens, and the image pickup device,the shutter, the focus detector, and the release controller are includedin the body unit.
 15. The apparatus of claim 14, wherein theexchangeable lens further comprises: a lens storage unit that storespower consumption information; and a communicator that transmits thepower consumption information to the body unit, wherein the releasecontroller determines whether the focus lens is driven in the sectionaccording to the power consumption information.
 16. The apparatus ofclaim 14, wherein the exchangeable lens further comprises: a focus lensdriver that drives the focus lens; a storage unit that stores drivingspeed information of the focus lens driver; and a communicator thattransmits the driving speed information to the body unit, wherein therelease controller determines whether the focus lens is driven in thesection according to the driving speed information.
 17. The apparatus ofclaim 14, wherein the exchangeable lens further comprises: a focus lensdriver that drives the focus lens; a storage unit that stores at leastone piece of information of focus driving sensitivity information, focuslens driver information, and backlash information of the focus lens; anda communicator that transmits the at least one information to the bodyunit, wherein the release controller determines whether the focus lensis driven in the section according to the at least one piece ofinformation.
 18. The apparatus of claim 14, wherein the body unitfurther comprises a display unit that displays a captured image, andstops a display on the display unit when the release controller drivesthe focus lens in the section.
 19. The apparatus of claim 14, whereinthe body unit further comprises: a release director that directs arelease operation that drives the focus lens and an iris to beperformed, and the release controller directs the focus lens to bedriven in the section when the release director directs continuousphotographing.
 20. The method of claim 9, wherein the release controllerdirects a focus lens included in the imaging lens to be driven in asection from a point of time when the shutter starts to be driven foropening the shutter to a point of time when the shutter stops to bedriven.
 21. A method of adjusting an auto focus of a digitalphotographing apparatus for capturing a still image according to ashutter signal, the method comprising: driving a focus lens to adjust afocus; and driving a shutter according to capturing operations of thestill image, wherein the focus lens is driven while driving the shutter.22. The method of claim 21, wherein the driving of the shuttercomprises: driving the shutter before starting light exposure forcurrent photographing; and driving the shutter after the light exposureis ended.
 23. The method of claim 22, wherein the focus lens is drivenfor the current photographing while driving the shutter before startingthe light exposure.
 24. The method of claim 22, wherein the focus lensis driven for following photographing while driving the shutter afterthe light exposure is ended.